title: Spectral properties of a divinyl chlorophyll a harboring mutant of Synechocystis sp. PCC6803.
abstract: A divinyl chlorophyll (DV-Chl) a harboring mutant of Synechocystis sp. PCC 6803, in which chlorophyll species is replaced from monovinyl(normal)-Chl a to DV-Chl a, was characterized. The efficiency of light utilization for photosynthesis was decreased in the mutant. Absorption spectra at 77 K and their fourth derivative analyses revealed that peaks of each chlorophyll forms were blue-shifted by 1-2 nm, suggesting lowered stability of chlorophylls at their binding sites. This was also true both in PSI and PSII complexes. On the other hand, fluorescence emission spectra measured at 77 K were not different between wild type and the mutant. This indicates that the mode of interaction between chlorophyll and its binding pockets responsible for emitting fluorescence at 77 K is not altered in the mutant. P700 difference spectra of thylakoid membranes and PSI complexes showed that the spectrum in Soret region was red-shifted by 7 nm in the mutant. This is a characteristic feature of DV-Chl a. Microenvironments of iron-sulfur center of a terminal electron acceptor of PSI complex, P430, were practically the same as that of wild type.
authors.affiliation: Department of Life Science, Graduate School of Life Science, University of Hyogo, Ako, Hyogo, 678-1297, Japan.
authors.forename: Md Rafiqul
authors.initials: MR
authors.lastname: Islam
authors.forename: Koji
authors.initials: K
authors.lastname: Watanabe
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kashino
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Satoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koike
mesh_terms: D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism*; D004583:Electrons; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D046939:Synechocystis / Q000378:metabolism*; D020524:Thylakoids / Q000378:metabolism; D014753:Vinyl Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007506:Iron-Sulfur Proteins; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D014753:Vinyl Compounds; C510432:divinyl chlorophyll a; D002734:Chlorophyll